HP 3000 Manuals HP 3000 Manuals
Running HP C/iX Programs
You can run HP C/iX programs using the RUN command or by entering the
program name (an implied run). You can pass parameters to the main
program and redirect the standard input (stdin), standard output
(stdout), and error output (stderr) to specific files by using the INFO
string.
Program Parameters
You can pass parameters to an HP C/iX program by declaring them in the
function main as shown in the following example:
main(argc, argv, envp, parm, info)
int argc;
char *argv[];
char *envp[];
int parm;
char *info;
NOTE The envp parameter is required as a placeholder in the formal
parameter list for main. This parameter is not initialized on
MPE/iX and must not be used. It is provided for compatibility with
programs on other systems that pass envp to main.
You invoke the program (called MYPROG) with the following command:
RUN MYPROG; INFO="STR1 STR2 STR3"; PARM=11
The C compiler separates the INFO string into argv arguments using blanks
as argument delimiters and sets argc to the number of argv elements. To
pass an argument that contains embedded blanks, enclose the argument in
quotes. Use single quotes to delimit the argument if the INFO string is
enclosed in double quotes; use double quotes if the INFO string is
enclosed in single quotes. A quote may be included within a quoted
string by escaping the quote with another quote similar to the manner in
which the MPE/iX command interpreter allows quotes to be passed in the
INFO string. The argv[0] argument is set equal to the program name, and
argv[argc] is set equal to NULL. The PARM and INFO values are passed
unchanged to the program. The order of the declaration of parameters to
main is significant, but the names of the formal parameters can be any
valid identifier. For the previous RUN command:
argv[0] = MYPROG.MYGROUP.MYACCT
argv[1] = "STR1"
argv[2] = "STR2"
argv[3] = "STR3"
argv[4] = NULL
argc = 4
parm = 11
info = "STR1 STR2 STR3"
To include blanks within a single entry in the argv array, the following
command:
RUN MYPROG; INFO="STR1 'STR2 WITH BLANKS' STR3"
yields:
argv[0] = MYPROG.MYGROUP.MYACCT
argv[1] = "STR1"
argv[2] = "STR2 WITH BLANKS"
argv[3] = "STR3"
argv[4] = NULL
argc = 4
info = "STR1 'STR2 WITH BLANKS' STR3"
To include a single quote in a single quoted argument, the following
command:
RUN MYPROG; INFO="STR1 'STR2 WITH QUOTE HID' 'DEN' STR3"
yields:
argv[0] = MYPROG.MYGROUP.MYACCT
argv[1] = "STR1"
argv[2] = "STR2 WITH QUOTE HID'DEN"
argv[3] = "STR3"
argv[4] = NULL
argc = 4
info = "STR1 'STR2 WITH QUOTE HID' 'DEN' STR3"
A maximum of 1023 argv[] entries are allowed and the maximum length of
the info string is 279 characters.
Redirection of Standard Files
The special characters <, >, >>, and & may be specified in the INFO
string to redirect standard files for a compiled HP C/iX program. The
special characters are described in the following table.
Table 8-3. Redirection Characters
---------------------------------------------------------------------------------------------
| | |
| Character | Description |
| | |
---------------------------------------------------------------------------------------------
| | |
| < | The name immediately following this symbol in the INFO string is |
| | considered a file name and the standard input for the program is read |
| | from that file. |
| | |
---------------------------------------------------------------------------------------------
| | |
| > | The name immediately following this symbol in the INFO string is |
| | considered a file name and the standard output of the program is sent |
| | to that file. |
| | |
---------------------------------------------------------------------------------------------
| | |
| >> | The name immediately following this symbol in the INFO string is |
| | considered a file name and the standard output of the program is |
| | appended to the end of the file. |
| | |
---------------------------------------------------------------------------------------------
| | |
| & | When included after > or >>, this character redirects the diagnostic |
| | output as well as the standard output to the specified file. The |
| | diagnostic output cannot be redirected separately from standard |
| | output. |
| | |
---------------------------------------------------------------------------------------------
The redirection characters and the file names which follow these
characters do not appear in the argv vectors or the argc count. For
example,
RUN MYPROG; INFO= "FILE1 FILE2 >& OUTFILE"
runs MYPROG with FILE1 and FILE2 passed in argv and redirects both the
diagnostic output and the standard output to the file OUTFILE. In this
example, argc is set to 3.
The Fileset Wildcard Feature
If the fileset wildcard feature is selected when the program is linked,
the INFO string handler for a compiled HP C/iX program expands valid
fileset wildcards into fully qualified permanent file names and passes
them into the main program through the argv vectors. To use the wildcard
feature, add the relocatable library LIBCWC.LIB.SYS to the FROM list when
linking your program. If this file is not in the FROM list, the wildcard
feature is not enabled. The CCXLLK and CCXLGO commands do not include
this library when linking.
Example.
LINK FROM=MYOBJ,LIBCWC.LIB.SYS; RL=LIBCINIT.LIB.SYS; TO=MYPROG
This example enables the wildcard feature for INFO strings passed to
MYPROG.
The fileset wildcards characters for an HP C/iX program are @, ?, and #.
They are based on the standard MPE/iX wildcards recognized by commands
and subsystems. The wildcard characters are described in the following
table.
Table 8-4. Fileset Wildcard Characters
--------------------------------------------------------------------------------------------
| | |
| Character | Description |
| | |
--------------------------------------------------------------------------------------------
| | |
| @ | Specifies zero or more alphanumeric characters. When used |
| | by itself, @ represents all members of a set. |
| | |
--------------------------------------------------------------------------------------------
| | |
| # | Specifies a single numeric character. |
| | |
--------------------------------------------------------------------------------------------
| | |
| ? | Specifies a single alphanumeric character. |
| | |
--------------------------------------------------------------------------------------------
These characters can be used as follows:
Character Description
n@ Represents all filenames starting with the
character n.
@n Represents all filenames ending with the character
n.
n@x Represents all filenames starting with the
character n and ending with the character x.
n####### Represents all filenames starting with the
character n followed by a maximum of seven digits.
?n@ Represents all filenames whose second character is
n.
n? Represents all 2-character filenames starting with
the character n.
?n Represents all 2-character filenames ending with
the character n
NOTE Each wildcard character is one of the 8-character limit for
account, group, and filename. A valid wildcard fileset must start
with an alphabetic character, an @, or a ?. Invalid wildcard
filesets are passed unaltered to the main program.
Example.
If the permanent files in the group and account MYGROUP.MYACCT contains
FILE1, FILEX, MYFILE, and MYPROG, the following:
RUN MYPROG; INFO="@ FILE# FILE?"
yields:
argv[0] = "MYPROG.MYGROUP.MYACCT" /* name of program */
argv[1] = "FILE1.MYGROUP.MYACCT" /* @ */
argv[2] = "FILEX.MYGROUP.MYACCT" /* @ */
argv[3] = "MYFILE.MYGROUP.MYACCT" /* @ */
argv[4] = "MYPROG.MYGROUP.MYACCT" /* @ */
argv[5] = "FILE1.MYGROUP.MYACCT" /* FILE# */
argv[6] = "FILE1.MYGROUP.MYACCT" /* FILE? */
argv[7] = "FILEX.MYGROUP.MYACCT" /* FILE? */
argv[8] = NULL
argc = 8
info = "@ FILE# FILE?"
If no files are found in the fileset, or an error occurs in attempting to
expand a wildcard fileset, a diagnostic message is printed to $STDLIST
and the process terminates immediately. Attempting to use a wildcard
fileset that would expand the number of argv elements beyond the 1023
element maximum also results in an error.
Escaping Special INFO String Characters
Special INFO string characters are characters that have special meaning
to the C INFO string parser. They include the standard I/O redirection
characters <, >, and &, as well as the fileset wildcard characters @, ?,
and # if the wildcard feature is enabled. If you wish to pass strings
containing these characters into a program in the argv vectors, you must
enclose these strings with either single or double quotes. Use single
quotes if your INFO string is delimited with double quotes, and double
quotes if your INFO string is delimited with single quotes. This will
disable their special functions and cause the INFO string parser to pass
them along to the main program.
Example.
RUN MYPROG; INFO ="'@' '<IDENTIFIER>'"
yields:
argv[0] = "MYPROG.MYGROUP.MYACCT"
argv[1] = "@"
argv[2] = "<IDENTIFIER>"
argv[3] = NULL
argc = 3
info = "'@' '<IDENTIFIER>'"
HP C/iX and Job Control Words
When an HP C/iX program terminates normally, a special job control word,
CJCW, is set to the exit value of the program. It contains the value of
the parameter passed to the C library routine exit, or _exit, or the
value returned from the function main if exit is not explicitly called.
The convention for C programs is to exit with a nonzero value if an error
condition has occurred, or exit with zero if no errors have occurred.
CJCW could be used for checking the exit value of a program in a job
file, or programmatically checking the exit value of a child process.
[REV BEG] The value of CJCW is unpredictable if [REV END] the function
main does not take care to return a value or if the exit function is not
explicitly called.
Examples
main() {
.
.
exit(7);
}
or
main() {
.
.
return(7);
}
Either of the above examples sets CJCW to the value of 7 on program
termination.
If a C program calls the C library routine abort, the system job control
word JCW is set to FATAL and a diagnostic message is printed to $STDLIST.
CJCW is set to a nonzero value.
Arithmetic Traps
C/iX programs execute with all arithmetic traps disabled. The C program
startup routines call the ARITRAP intrinsic with an argument of zero to
disable the traps.