mkstr(CP)                      6 January 1993                      mkstr(CP)


 Name

    mkstr - creates an error message file from C source

 Syntax

    mkstr [-] messagefile prefix file...

 Description

    mkstr is used to create files of error messages.  Its use can make pro-
    grams with large numbers of error diagnostics much smaller, and reduce
    system overhead in running the program as the error messages do not have
    to be constantly swapped in and out.

    mkstr will process each specified file, placing a massaged version of the
    input file in a file whose name consists of the specified prefix and the
    original name.  The optional dash (``-'') causes the error messages to be
    placed at the end of the specified message file for recompiling part of a
    large mkstred program.

    A typical mkstr command line is:

       mkstr pistrings xx *.c

    This command causes all the error messages from the C source files in the
    current directory to be placed in the file pistrings and processed copies
    of the source for these files to be placed in files whose names are pre-
    fixed with xx.

    To process the error messages in the source to the message file, mkstr
    keys on the string `error("' in the input stream.  Each time it occurs,
    the C string starting at the `"' is placed in the message file followed
    by a null character and a newline character; the null character ter-
    minates the message so it can be easily used when retrieved, the newline
    character makes it possible to sensibly cat the error message file to see
    its contents.  The massaged copy of the input file then contains a lseek
    pointer into the file which can be used to retrieve the message.  For
    example, the command changes

       error(``Error on reading'', a2, a3, a4);

    into

       error(m, a2, a3, a4);

    where m is the seek position of the string in the resulting error message
    file.  The programmer must create a routine error which opens the message
    file, reads the string, and prints it out.  The following example illus-
    trates such a routine.

       char    efilname[] =  "/usr/lib/pi_strings";
       int     efil = -1;

       error(a1, a2, a3, a4)
       int a1, a2, a3, a4;
       {
               char buf[256];

               if (efil < 0) {
                       efil = open(efilname, 0);
                       if (efil < 0) {
                               perror(efilname);
                               exit(1);
                       }
               }
               if (lseek(efil, (long) a1, 0) ||
                         read(efil, buf, 256) <= 0) {
                       printf("Unable to find error msg ");
                       printf("at seek address %d\n",a1);
                       exit(1);
                       }
               printf(buf, a2, a3, a4);
       }


 Notes

    All the arguments except the name of the file to be processed are
    optional.

 See also

    lseek(S), xstr(CP)

 Standards conformance

    This utility was developed at the University of California at Berkeley
    and is used with permission.