I
Ian Collins
argv[0] ?Albretch said:
A
Albretch Mueller
I need to get the name of the very code running in order to include it in a
time stamped log file.
..
As I remember, there is an ANSI standard way to ask a running program for
its name. But I forgot the specifics of it.
..
How is it that you do that?
..
lbrtchx
time stamped log file.
..
As I remember, there is an ANSI standard way to ask a running program for
its name. But I forgot the specifics of it.
..
How is it that you do that?
..
lbrtchx
A
Andrew Poelstra
/* You must define main() this way: */
int main (int argc, char *argv[])
{
/* Code here */
return 0;
}
argc contains the number of arguments plus one, and argv[]
is the array of them. argv[0] is almost always the program
name, as Ian stated.
S
spibou
In the thread "Can u tell me the explanation reg this problem" Eric
Sosman
points out that it is not guaranteed by the standard that argv[0] will
not be a
NULL pointer and furthermore that the name of an executable may not be
uniquely defined. So it is not even clear what a standard function
would be
supposed to provide as "name of running code".
By the way is there a way to refer to a specific post in a newsgroup as
opposed
to thead title ?
Sosman
points out that it is not guaranteed by the standard that argv[0] will
not be a
NULL pointer and furthermore that the name of an executable may not be
uniquely defined. So it is not even clear what a standard function
would be
supposed to provide as "name of running code".
By the way is there a way to refer to a specific post in a newsgroup as
opposed
to thead title ?
W
Walter Roberson
Andrew Poelstra said:
On freestanding systems, argv[0] is unlikely to be the program name.
[NB: the standards indicate that if no program name is available,
then argv[0][0] shall be the null character.]
On Unix systems, argv[0] might be a path to the executable, or
might be just the last component of the path, or might be the
path without the file extension... or might be something totally
unrelated to the path, since most Unix systems allow the invoking
program to set the new argv[0] independantly of the path to the
executable.
The C89 standard does explicitly use the phrase "program name"
in the relevant clause explaining the "intent" of the values, but
there are a lot of different semantic interpretations about what
exactly a "program name" -is-.
A
Andrew Poelstra
True; but the OP wants logging, and logging implies a file system, which
implies that the executable is a file, which implies that it has a name.
Flimsy logic, obviously, but it may very well apply to the OP's situation.
Yes; I should have mentioned that.
Well, a log file should be aware of all that. I assume he needs the
name to write something like "myprog (10/10/10 10:10AM): Deleted home
folder" to the log file. If he's using argv to determine the folder
name, it is true that that is unreliable.
True;
A
Andrew Poelstra
Quote context. Judging by your GMail address, I assume that you are using
GGroups, and you should take note of the following:
Click 'More Options' and then 'Add Reply'. Don't use the broken reply link
at the bottom of the post. See CBFalconer's sig for more information.
The answer to your last question is yes. You can refer to it by <where newsid will be a long random-looking string available when you click
'More Options'.
A
Andrew Poelstra
Should have been a period there, not a semicolon. I have no additions to
that thought.
D
Dik T. Winter
But not always. It can be an empty string, and the contents can also
be thoroughly misleading.
S
spibou
Andrew said:
I'm not sure what context you would have me quote in this case , the
whole
Sosman post I was referring to ?
I don't see any "More Options" link. I have clicked on the links on
someone's
signature , can't remember who , and read what was there. As far as I
can remember
it was talking about top-posting and I haven't done that.
If I click on "show options" and then on "Show original" I get the
header. On the header
there is a line starting with "Message-ID:". Is this what you are
referring to ?
C
CBFalconer
Not reliably. There is no reason to assume that any such specific
post is available to your reader. That is why we always include
adequate context.
--
"Our enemies are innovative and resourceful, and so are we.
They never stop thinking about new ways to harm our country
and our people, and neither do we." -- G. W. Bush.
"The people can always be brought to the bidding of the
leaders. All you have to do is tell them they are being
attacked and denounce the pacifists for lack of patriotism
and exposing the country to danger. It works the same way
in any country." --Hermann Goering.
N
Nelu
Here are a few useful links:
http://cfaj.freeshell.org/google/
http://www.caliburn.nl/topposting.html
http://www.netmeister.org/news/learn2quote.html
It seems that the Reply link works correctly now in
Google Groups.
It may be just a temporary thing so you may find
the first link I gave you still useful.
D
Default User
See below. As of this time, the US version seems to have changed to
quoting with the default reply.
Brian
N
Nelu
Since we are a little OT:
Although I have nothing against anyone's opinion toward
politics, no matter if they are right, wrong or gray, I think
your old signature (Google netiquette) was much more useful
.
E
Eric Sosman
Andrew said:
Non sequitur. "The executable" could be a nameless chunk
of code permanently burned into ROM, but could nonetheless work
with "files" on other sorts of media. Going back further yet,
logging does not imply a file system: the log data might just
be "fire and forget" across a communications link, perhaps to a
hard-copy printer or a remote telemetry hookup.
Still, though, argv[0] is usually a good tag for log
entries. On days when I'm feeling particularly paranoid I'll
write things like
static const char *progname = __FILE__;
...
int main(int argc, char *argv[]) {
if (argv[0] != NULL && argv[0][0] != '\0')
progname = argv[0];
...
...
...
if (something_went_wrong) {
perror (progname);
exit (EXIT_FAILURE);
} ...
Then I usually shake my head ruefully over such an overblown
"belt *and* suspenders" attitude, and overreact foolishly by
omitting all error-checking in my next three programs. ;-)
(I must confess that I actually have written code like
the above, and that never once has it proven necessary ...)
A
Andrew Poelstra
Sure. It'd better than nothing.
I meant 'Show options'. Sorry about that.
Yep. Glad you thought to click 'Show Original'; I wouldn't have remembered to
tell you that.
A
Albretch Mueller
OK, this is what/how I did it, which caomplied without errors or wanings
using the compiler flags: "-ansi -pedantic -Wall"
..
and BTW I am obviously working with some plain files (off a file system)
..
/* x platform (standard ANCI C) */
#include <stdio.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
char *getYYYYmmDDHHMMSS(char*, time_t);
int main(int argc, char **argv){
time_t start_t;
int iR;
char *aLogFl;
FILE *LOGFL = NULL;
struct tm *timeinfo;
iR = EXIT_FAILURE;
if((argv != NULL) && (argv[0] != NULL) && (strlen(argv[0]) > 0)){
iR = EXIT_SUCCESS;
time(&start_t);
aLogFl = getYYYYmmDDHHMMSS(argv[0], start_t);
if((LOGFL = fopen(aLogFl, "w+t")) == NULL){
fprintf(stderr, "\n Cannot open log file: %s\n", aLogFl);
goto end;
}
timeinfo = localtime (&start_t);
fprintf(LOGFL, "// __ run date and time are: %s", asctime (timeinfo));
fprintf(LOGFL, "// __ log file is: %s\n", aLogFl);
}
if(LOGFL != NULL){ fclose(LOGFL); }
end:;
exit(iR);
}
char *getYYYYmmDDHHMMSS(char *KdNm, time_t start_t){
int i, iSL = strlen(KdNm), ISS = 0, iBuf, iSz;
char *aKdNm02 = NULL;
char *aLogFl = NULL;
/* gcc [.|./] "/usr/bin/ld: [*]: No such file: File format not recognized"
*/
if(strncmp("./", KdNm, 2) == 0){ ISS = 2; }
else if(strncmp(".", KdNm, 1) == 0){ ISS = 1; }
iBuf = (iSL - ISS) + 1;
aKdNm02 = (char *)malloc(iBuf);
for(i = 0; (i < (iSL - ISS)); ++i){ aKdNm02 = KdNm[i + ISS]; }
iSz = strlen("YYYYMMDDHHMMSS_") + strlen(aKdNm02) + strlen(".log") + 1;
aLogFl = (char*)malloc(iSz);
strftime(aLogFl, sizeof("YYYYmmDDHHMMSS"), "%Y%m%d%H%M%S",
localtime(&start_t));
strcat(aLogFl, "_"); strcat(aLogFl, aKdNm02); strcat(aLogFl, ".log");
return(aLogFl);
}
using the compiler flags: "-ansi -pedantic -Wall"
..
and BTW I am obviously working with some plain files (off a file system)
..
/* x platform (standard ANCI C) */
#include <stdio.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
char *getYYYYmmDDHHMMSS(char*, time_t);
int main(int argc, char **argv){
time_t start_t;
int iR;
char *aLogFl;
FILE *LOGFL = NULL;
struct tm *timeinfo;
iR = EXIT_FAILURE;
if((argv != NULL) && (argv[0] != NULL) && (strlen(argv[0]) > 0)){
iR = EXIT_SUCCESS;
time(&start_t);
aLogFl = getYYYYmmDDHHMMSS(argv[0], start_t);
if((LOGFL = fopen(aLogFl, "w+t")) == NULL){
fprintf(stderr, "\n Cannot open log file: %s\n", aLogFl);
goto end;
}
timeinfo = localtime (&start_t);
fprintf(LOGFL, "// __ run date and time are: %s", asctime (timeinfo));
fprintf(LOGFL, "// __ log file is: %s\n", aLogFl);
}
if(LOGFL != NULL){ fclose(LOGFL); }
end:;
exit(iR);
}
char *getYYYYmmDDHHMMSS(char *KdNm, time_t start_t){
int i, iSL = strlen(KdNm), ISS = 0, iBuf, iSz;
char *aKdNm02 = NULL;
char *aLogFl = NULL;
/* gcc [.|./] "/usr/bin/ld: [*]: No such file: File format not recognized"
*/
if(strncmp("./", KdNm, 2) == 0){ ISS = 2; }
else if(strncmp(".", KdNm, 1) == 0){ ISS = 1; }
iBuf = (iSL - ISS) + 1;
aKdNm02 = (char *)malloc(iBuf);
for(i = 0; (i < (iSL - ISS)); ++i){ aKdNm02 = KdNm[i + ISS]; }
iSz = strlen("YYYYMMDDHHMMSS_") + strlen(aKdNm02) + strlen(".log") + 1;
aLogFl = (char*)malloc(iSz);
strftime(aLogFl, sizeof("YYYYmmDDHHMMSS"), "%Y%m%d%H%M%S",
localtime(&start_t));
strcat(aLogFl, "_"); strcat(aLogFl, aKdNm02); strcat(aLogFl, ".log");
return(aLogFl);
}