z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

If you compile an MVS data set source using the -g option, you can use
dbx to perform source-level debugging for the executable file. You must first
issue the dbx use subcommand to specify a path of double slash (//),
causing dbx to recognize that the symbolic name of the primary source file
is an MVS data set. For information on the dbx command and its use
subcommand, see “use subcommand for dbx: Set the list of directories to
be searched” on page 227.
For more information on using dbx, see z/OS UNIX System Services
Programming Tools.
The z/OS UNIX System Services web page also has more information
about dbx. Go to http://www.ibm.com/servers/eserver/zseries/zos/unix/.
For more information on the _BPX_PTRACE_ATTACH environment
variable, see z/OS UNIX System Services Programming: Assembler
Callable Services Reference.
The GONUMBER option is automatically turned on by the -g option, but
can also be turned on independently. There is no execution path overhead
incurred for turning on this option, only some additional space for the saved
line number tables.
For 31-bit compiles and In Storage Debug (ISD) information, the
GONUMBER option generates tables that correspond to the input source
file line numbers. These tables make it possible for Debug Tools and for
error trace back information in CEE dumps to display the source line
numbers. Having source line numbers in CEE dumps improves
serviceability costs of applications in production. The z/OS XL C/C++ User’s
Guide contains more information on the GONUMBER compiler option.
Example: The following is an example of compiling with the GONUMBER
compiler option:
c89 -o outfile -Wc,’GONUM’ file.c
c89, cc, and c++
Note: -g forces the NOOPTIMIZE compiler option regardless of its position
in the command line.
-I directory
Note: The I option signifies an uppercase i, not a lowercase L.
-I specifies the directories to be used during compilation in searching for
include files (also called header files).
Absolute pathnames specified on #include directives are searched exactly
as specified. The directories specified using the -I option or from the usual
places are not searched.
If absolute pathnames are not specified on #include directives, then the
search order is as follows:
1. Include files enclosed in double quotes (") are first searched for in the
directory of the file containing the #include directive. Include files
enclosed in angle-brackets (< >) skip this initial search.
2. The include files are then searched for in all directories specified by the
-I option, in the order specified.
3. Finally, the include files are searched for in the usual places. (See
Usage Note 4 on page 98 for a description of the usual places.)
Chapter 2. Shell command descriptions 73