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	root->[0]next->name
	root->[0]next->type

Questions and Answers
Q:	Why can't I invoke ups without any arguments and then instruct it to debug a program ?
A:	ups was designed from the start to get its target name from the command line. You can also supply the target arguments on the command line with the -a option. See ups Command Line Arguments. You can also add or edit arguments within ups by editing the target text at the top of the display window. See Target Command Line Arguments. You can also attach and detach to specific instances of the target from within ups via the attach and detach buttons - see The Source Region.
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Q:	How can I cut and paste text in ups ?
A:	Pan with the left mouse button down to select text, and ^y to paste the text selection in. See the Cut and Paste section for details.
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Q:	I have a very large program and ups takes forever to come up. Can the speed be improved ?
A:	ups does a prescan of global symbols and addresses on invocation. This allows you to put breakpoints in shared libraries (such as printf in libc) before the libraries are actually mapped in. An application may use dozens of libraries, but typically you are only interested in debugging a small set. You can tell ups not to load any symbols for specified libraries by using the noload or load statements in a ~/.upsinit file. In this way the invocation time can be dramatically reduced. See the Initialization file for more details. Unloaded libraries can be interactively loaded on demand with the rescan init file caption in the target menu.
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Q:	I want to see how some data in heap changes from one point to another. If I click on such a variable where it is created, it may be out of context and not displayed at another point. How can I make the display permanent ?
A:	Place an add expr high up in the stack (such as main), or in a source file where the data type is used. The expression should be a typecast of the variable address to the right data type. For example, for a variable displayed like struct func_s **<p_initfunc> 0x14d56c the expression would be (struct func_s **)0x14d56c. The expression can be expanded, and cont pressed. Then when ups next stops, either at a breakpoint or by pressing the stop button, any changed data members will be shown in the highlight color (default is red). In most cases you can copy the variable line in the display window, click on the function name, press add expr, then paste and edit the string with this custom menu string: # this is to change a variable to an `add exp' of the address setenv UPS_F5_STR "^y@b^ @b^w^b^d)^a(\n"
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Q:	The pause() instruction in my program no longer works in Solaris. Why ?
A:	The pause() functionality in Solaris is different from SunOS. In order to make pause() work, you need to add a dummy signal handler for SIGCONT for a pause to work. For example: static void dummy_cont(int sig) {} main() { signal(SIGCONT,dummy_cont); pause(); }
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Q:	My program has the dummy signal handler for SIGCONT, and it is stopped at a pause(), but when I attach ups, why does the stack show <bad text address> ?
A:	The symbols for the C library are not loaded. Check your ~/.upsinit file for statements like noload *libc*.
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Q:	The scrollbars work in the opposite direction from what I expect. Can this be changed ?
A:	Yes - set the ScrollbarType X resource to anything other that ups, such as MOTIF. Then scrolling will move the viewport in the opposite direction to the mouse movement, this being the convention used by most X toolkits. See the X Resources section. One might point out that the industry standard for this is contrary to the action of a real scroll of paper, in which the viewport remains fixed and the paper in moved through the viewport onto the rollers. The ups scrollbar emulates moving the paper with the viewport fixed: other scrollbars apparently suggest keeping the paper fixed and moving the viewport.
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Q:	Can I position the scrollbars on the right, instead of the left ?
A:	The undocumented SHIFT+CONTROL with left/right button combinations can do this. However there is currently a bug in that scroolbars on the right display no elevator blob.
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Q:	It is sometimes laborious to expand and collapse objects by always having to select them, then move the mouse up to the top menu to perform the action. Is there a quicker way ?
A:	Yes - see the Accelerators in the Display Area section. SHIFT - left click generally toggles between expanding and collapsing the object.
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Q:	My display window often shows too much data. I might be interested in seeing just a couple of data components in the third level of a nested struct, but expanding the intermediate levels uses too much space and obscures the stack.
A:	There are several solutions for this. First, create a ups-state directory before invoking ups, then having displayed the data in the desired form, it can be restored in a later session to the "like before" state. See the Saving State section for details. Consider the following example: func_t <f{0}> *0x1ddfb8 short <fu_flags> 0 char <fu_name{0}> "main" char <fu_demangled_name{0}> "main" type_t <fu_type{0}> *NULL unsigned long <fu_addr> 458916 fil_t <fu_fil{0}> *0x1dbdc0 char <fi_name{0}> "ups.c" char <fi_name_only{0}> "ups.c" char <fi_path_hint{0}> "/bs/ups-3.31-RGA/ups/" char <fi_source_path{0}> "/bs/ups-3.31-RGA/ups/" language_t <fi_language> LANG_C short <fi_flags> 0 symtab_t *<fi_symtab> 0x148948 char <fi_data{0}> "" undefined struct Srcbuf *<fi_srcbuf> 0x0 block_t *<fi_block> 0x1dbd98 funclist_t *<fi_funclist> 0x1ddb00 fil_t *<fi_next> 0x1dc628 language_t <fu_language> LANG_C symtab_t *<fu_symtab> 0x148948 undefined struct cblist_s *<fu_cblist> 0x0 func_t *<fu_next> 0x1dea28 char <fu_predata{0}> *NULL char <fu_symdata{0}> "" undefined struct statement_s *<fu_statement> 0x0 lexinfo_t *<fu_lexinfo> 0x0 lno_t *<fu__lnos> 0x0 short <fu_max_lnum> 21331 block_t *<fu__blocks> 0x0 When the specific data element appears in the source window, a left click on the text will display just the desired element: for instance if f->fu_fil appears in the source, a left click on the first f displays: func_t <f{0}> *0x1ddfb8 whereas a left click on fu_fil displays: func_t <f{0}> *0x1ddfb8 fil_t <fu_fil{0}> *0x1dbdc0 Suppose you are only interested in the fi_name and fi_name_only members. One method is to fully expand all levels of the struct and then select and delete unwanted members. Note that collapsing to the top level will not delete expanded data members. To eliminate all other data, left click on the fi_path_hint line and drag vertically down to the fi_next line. Be carefully not to stray horizontally too far - see the X selection threshold description in Cut and Paste. The display window will scroll if necessary. Then press del to delete the unwanted data. To eliminate data in the func_t struct, simply SHIFT-left click on the func_t line, this being an accelerator for collapsing to the first level. The net results will be: func_t <f{0}> *0x1ddfb8 fil_t <fu_fil{0}> *0x1dbdc0 char <fi_name{0}> "ups.c" char <fi_name_only{0}> "ups.c" An alternative is to select the fully collapsed func_t object, then enter .fu_fil->fi_name .fu_fil->fi_name_only <RET> in the typing line. This method provides a great deal of flexibility. See Examining Linked Data Structures. You can even put such commonly used dereference strings in a pop up menu - see the custom menu description in Environment Variables Affecting ups.
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Q:	My program is linked to code that our customers write. It has SIGSEGV and SIGBUS signal handlers in order to recover from errors in the user code. However when debugging with ups, the program is terminated on a user error, when in fact it is capable of recovering and continuing. How can I tell ups not to kill off the target ?
A:	See the Special handling for SIGSEGV and SIGBUS section. Essentially, the signals should be set to Stop - accept signal on continue.
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Q:	Sometimes when I paste expressions into the source area, ups objects to preprocessor macros such as NULL or FALSE. How can I get ups to understand these ?
A:	Use a ups-state/repltab file to define such strings. See Pasting Expressions from the Source Window for details.
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Q:	ups crashes on invocation with my target. Is there anyway to do some debugging ?
A:	ups has probably encountered some syntax in a library that it can't deal with. A work-around is to not load symbols for such libraries. Set the environment variable VERBOSE to 1 and start ups again. It should list the library that caused the crash. Then put a noload statement for this library in your ~/.upsinit file, for example: noload *my_library*
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Q:	How can I see long strings in the display window ?
A:	There are several methods. You can select the line and use the snapshot menu to dump it to the bottom output window which does line wrapping. For single indexed strings, you can do a Dup which will duplicate the string, but with the index bumped by 40. You can also manually edit the index to change the start of the string (perhaps using the bump keys - see Expressions in the Display Area). Finally, you can copy the text by vertically panning across the line with the cursor to the left of the text. It can then be pasted elsewhere, including the output window - seee Editing in the Output Window.
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Q:	I have several expressions, created via add expr, to view different components of a linked list using the ->[] syntax as shown below. I can traverse the list by bumping the index, but this only affects the expression I am editing. How can I change many expressions at once ? root->[0]next->name root->[0]next->type
A:	If possible, change the expressions to use a local or global variable, such as: root->[i]next->name root->[i]next->type where i is some integer. Then create a scratch line of breakpoint code to bump its value: i++; Select the code and repeatedly execute it by pressing the execute caption at the top of the display window. This will cause all affected expressions to change at the same time. The variable may have to be inialized beforehand and reset afterwards - do this by editing the value in the display window.
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Q:	I am using Purify on my application, and want to repeated call a Purify API to check for memory state as I step down lines of source code. How can I do this without putting breakpoint code after every line ?
A:	Use just one line of breakpoint code. Whenever you need to call the API, select the breakpoint and press the execute button.
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Q:	I don't want ups to upset the colormap of my application so I use the -mono command line option. However this means that I lose the highlight and variable colors. Is there any way to get this information back ?
A:	The UnderlineVars X resource (see X Resources) can be set to underline variable names. In a later version of ups you will be able to do the same for data that is highlighted.
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Q:	How can I make a conditional breakpoint on a 'long long' integer ?
A:	Because the interpreter does not support long long types, there is a trick for making conditional breakpoints for such numbers. The workaround is to use pointers in breakpoint code. You can check all 8 bytes by casting each 4 bytes to a long. (This assumes the 8 bytes are contiguous; works on Solaris, but may not for Linux.) e.g. if long long ll = 0x123456789abcdef0 use this for a conditional breakpoint: if (*((long*)&ll) == 0x12345678 && *((long*)&ll+1) == 0x9abcdef0) #stop; You could make an editing macro to simplify it: setenv UPS_F1_STR '^e^uif(*((long*)&^y)==0x0 && *((long*)&^y+1)==0x0) #stop;' 1. Create a breakpoint (#stop;). 2. Select the variable (ll). 3. Middle click anywhere in the stop line, then right click.
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Q:	How do I instruct ups to follow the child process after doing a 'fork()/exec()' ?
A:	You can follow the child using just one instance of ups: 1. Start ups on the parent: ups parent & 2. In the parent add a breakpoint and calls to kill() and printf(): if ((child_pid = vfork()) == FALSE) { /* this is the child */ .... } else { /* this is the parent */ kill (child_pid, 23); <<< insert this breakpoint code. 23 is SIGSTOP printf ("child pid is %d\n", child_pid); <<< breakpoint code to get pid .... } #stop; <<< stop here to follow the child 2. At the #stop, edit the target name to the child name, press RET. 3. Attach ups to the child <pid>. 4. From an xterm, continue the child: kill -CONT <pid> 5. In ups, put a break on main() or whatever, and continue.
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Written by Rod Armstrong.
HTML version by Ian Edwards.