I guess there's more than one way to solve a problem. :) The initial setting of EVR was there just to show that you can also use the variable in the C program using getenv(). Your solution works fine if there's only one env var to set (apart from some other practical problems that may arise). When you want to set multiple env vars, it wouldn't work.
But I must agree, since the initial question only mentioned one env var, your solution is the simpler one. :) Kind regards, Sander -----Oorspronkelijk bericht----- Van: Tivy, Robert [mailto:rt...@ti.com] Verzonden: do 18-12-2008 13:02 Aan: Sander Huijsen; davinci-linux-open-source@linux.davincidsp.com Onderwerp: RE: A way to export from c an environment var This is overly complex. The initial setting of env var EVR at the beginning of the script does nothing, and the C program is just using the environment to store a temp value, which isn't even needed. The usage of a file is also unnecessary (unless you want to retain the value). This would do the same thing... #!/bin/sh EVR=`./your_c_program` Or in csh #!/bin/csh setenv EVR `./your_c_program` With the C program being printf("%d", int_value); or printf(string_value); or whatever needs to be set in the env var. - Rob > -----Original Message----- > From: > davinci-linux-open-source-bounces+rtivy=ti....@linux.davincids > p.com > [mailto:davinci-linux-open-source-bounces+rtivy=ti....@linux.d > avincidsp.com] On Behalf Of Sander Huijsen > Sent: Thursday, December 18, 2008 6:08 AM > To: davinci-linux-open-source@linux.davincidsp.com > Subject: RE: A way to export from c an environment var > > Well yes, Arie, you are right about that. I did find a > clever/nasty (you be the judge of that) solution for the > problem. Simply write the environment variable from within > your application to a file, and then "source" the file in > your script. :-) > > The script might look something like this: > > [script] > #!/bin/sh > > # create some environment variable 'EVR' and show it > EVR="your value" > echo $EVR > > # run your C program, which changes EVR and exports it > to /tmp/evr.env > ./your_c_program > > # source the changed environment > source /tmp/evr.env > > # now show the changed value > echo $EVR > > # and exit the script. > exit 0 > [/script] > > > In your C program, you would do something like this: > > [snippet] > // Here, you change the environment variable > setenv("EVR", "my changed value", 1); > > // Open a temp file to write the environment variable in > FILE *fh = fopen("/tmp/evr.env", "w+"); > if (fh) > { > // This will write 'EVR="my changed value"' in > the temp file > fprintf(fh, "EVR=\"%s\"\n", getenv("EVR")); > fclose(fh); > } > [/snippet] > > > Regards, > Sander > > > -----Original Message----- > From: Arie de Muijnck [mailto:leon...@ademu.com] > Sent: Thursday, December 18, 2008 10:52 AM > To: Sander Huijsen; davinci-linux-open-source@linux.davincidsp.com > Subject: Re: A way to export from c an environment var > > Unless one wants to set a persistant value, that can be used > after his/hers process finishes... > > Unfortunately functions like setenv(), putenv(), > system("export ...") change only the current environment of > the process itself, not the 'global' > environment of the user (let alone the system). > > Regards, > Arie de Muijnck > > ----- Original Message ----- > > You might want to try setenv(). Just type 'man 3 setenv' in a Linux > > shell to get the man-page for that function (which is in stdlib). > > > > Sander > > > > > > -----Original Message----- > > Hi, > > > > Is there a way to create and export from c an environment > variable a > > bash script can be aware of? I intend something like PATH, etc. > > > > Thanks and Regards, > > > > VanVliet > > > > Dr. Caroline Van Vliet > > Adfl Group > > Advanced DSP Flexible Language Group > > Via Greto di Cornigliano 6R > > 16152 - Genova, Italy > > Tel. +39 010 8609370 - Fax +39 010 8609381 > > -------------------------------------------------------- > > > CONFIDENTIALITY NOTICE - This e-mail transmission, and any > documents, files or previous e-mail messages attached to it > may contain information that is confidential or legally > privileged. If you are not the intended recipient, or a > person responsible for delivering it to the intended > recipient, you are hereby notified that you must not read > this transmission and that any disclosure, copying, printing, > distribution or use of any of the information contained in or > attached to this transmission is STRICTLY PROHIBITED. If you > have received this transmission in error, please immediately > notify Sander Huijsen by telephone or > shuij...@optelecom-nkf.com and delete the original > transmission and its attachments without reading or saving in > any manner. > > _______________________________________________ > Davinci-linux-open-source mailing list > Davinci-linux-open-source@linux.davincidsp.com > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source > -------------------------------------------------------- CONFIDENTIALITY NOTICE - This e-mail transmission, and any documents, files or previous e-mail messages attached to it may contain information that is confidential or legally privileged. If you are not the intended recipient, or a person responsible for delivering it to the intended recipient, you are hereby notified that you must not read this transmission and that any disclosure, copying, printing, distribution or use of any of the information contained in or attached to this transmission is STRICTLY PROHIBITED. If you have received this transmission in error, please immediately notify Sander Huijsen by telephone or shuij...@optelecom-nkf.com and delete the original transmission and its attachments without reading or saving in any manner. _______________________________________________ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
