Open System Services System Calls Reference Manual (G06.25+, H06.03+)

System Functions (t) tdm_spawn(2)
envp[] Specifies an array of character pointers to null-terminated strings that describe
the environment for the new process.
pe_parms Points to the input structure containing Guardian process attributes to be
assigned to the new process. The structure is defined in the tdmext.h header file.
When this parameter contains a null pointer, the tdm_spawn() function assumes
default Guardian attributes. Otherwise, the structure must be defined locally and
initialized before its first use. Initialization is done using the
#define
DEFAULT_PROCESS_EXTENSION
,asdefined in the tdmext.h header file.
The initialized values can then be modified as appropriate for the call.
pr_results Points to the output structure containing optional process identification and error
information. In case of error, this structure provides additional information,
including the PROCESS_LAUNCH_ procedure error and error detail. The struc-
ture is defined in the tdmext.h header file.
The structure must be defined locally and initialized before its first use. Initiali-
zation is done by using the #define
DEFAULT_PROCESS_EXTENSION_RESULTS,asdefined in the tdmext.h
header file. |
See the process_extension_results(5) reference page for information about the |
content of the structure. The tdmext.h header file is not kept current when new |
error codes are defined for process creation functions. The list of _TPC_ macros |
described in that reference page is not complete; for a current description of error |
macros and error codes, see the Guardian header file |
$SYSTEM.ZSPIDEF.ZGRDC or the summary of process-creation errors in the |
Guardian Procedure Calls Reference Manual (see the table entitled "Summary |
of Process Creation Errors").
DESCRIPTION
The tdm_spawn() function creates a new process image. The new image is constructed from a
regular executable file, called a new process image file. The new process image file is formatted
as an executable text or binary file in one of the formats recognized by the tdm_spawn() func-
tion.
The tdm_spawn() function is similar to the tdm_spawnp() function. The main difference is the
way the pathname for the process image file is resolved. tdm_spawn() always resolves relative
pathnames by prefixing the current working directory; see Identifying the Process Image File,
later in this reference page. tdm_spawnp() sometimes uses the PATH environment variable to
resolve pathnames.
The tdm_spawn() function provides a different way to create a new process than the way pro-
vided by the tdm_fork() and tdm_execve() functions. tdm_spawn() provides a more efficient
way to create a new process to execute a new program file. However, tdm_spawn() does not
provide all the function provided by tdm_fork() and tdm_execve().
When a program is executed as a result of a tdm_spawn() call, it is entered as a function call:
int main(
int argc,
char ∗∗argv[],
char ∗∗envp);
Here, the argc parameter is the argument count, the argv[]parameter is an array of character
pointers to the arguments themselves, and the envp parameter is a pointer to a character array
listing the environment variables. The argv[]array is terminated by a null pointer. The null
pointer is not counted in argc.
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