mkudffs issues

Hello, when envoking 'system' from an application like the following code shows: // format media with UDF if( -1 == system( "/usr/bin/mkudffs --spartable=2 --media-type=cdrw --udfrev=0x0150 /dev/scd0" ) ) { fprintf( stderr, "OpticalDrive::formatMedia : format UDF : ERROR : %s\n", strerror( errno ) ); iRet = -1; } The system call itself does not give me a return of -1, so my error is not shown, but i see the following message: trying to change type of multiple extents If i execute the command in the command line, everything works ok. any comments? Should i do the system call with exec* instead? if so, why would it matter ? gustavo