DESCRIPTION
mkstr
examines a C program and creates a file
containing error message strings used by the program.
Programs with many error diagnostics can be made much smaller
by referring to places in the file,
and reduce system overhead in running the program.
mkstr
processes each of the specified
files,
placing a revised version of each in a file whose name
consists of the specified
prefix
concatenated in front of the original name.
A typical usage of
mkstr
would be
This command would cause all the error messages from the C source
files in the current directory to be placed in the file
mystrings
and revised copies of the source for these files to be placed in
files whose names are prefixed with
xx.
When processing the error messages in the source
for transfer to the message file,
mkstr
searches for the string
error(
in the input file.
Each time it is encountered, the C string starting after the leading quote
is placed in the message file,
followed by a null character and a newline character.
The null character terminates the message so that
it can be easily used when retrieved,
and the newline character makes it possible to conveniently
list the error message file (using
cat,
more,
etc.; see
cat(1)
and
more(1))
to review its contents.
The modified copy of the input file is identical to the original,
except that each occurrence of any string that was moved
to the error message file is replaced by an offset pointer usable by
lseek
to retrieve the message.
If the command line includes the optional
-,
extracted error messages are placed at the end
of the specified message file (append) instead of overwriting it.
This enables you to process individual files that are part
of larger programs that have been previously processed by
mkstr
without reprocessing all the files.
All functions used by the original program whose names end in
error
that also can take a constant string as their first argument should be
rewritten so that they search for the string in the error message file.
For example, a program based on the previous example usage would
resemble the following:
#include <stdio.h>
#include <sys/types.h>
#include <fcntl.h>
char errfile[] = "mystrings";
error(offset, a2, a3, a4)
int offset, a1, a2, a3;
{
char msg[256];
static int fd = -1;
if (fd < 0) {
fd = open(errfile, O_RDONLY);
if (fd < 0) {
perror(errfile);
exit(1);
}
}
if (lseek(fd, (off_t) offset, 0) || read(fd, msg, 256) <= 0) {
printf("? Can't find error message in %s:\n", errfile);
perror(errfile);
exit(1);
}
printf(msg, a1, a2, a3);
}
EXTERNAL INFLUENCES
Environment Variables
LC_CTYPE
determines the interpretation of comments and string
literals as single- and/or multibyte characters.
If
LC_CTYPE
is not specified in the environment or is set to
the empty string, the value of
LANG
is used as a default for each
unspecified or empty variable.
If
LANG
is not specified or is set to the empty string, a default of "C" (see
lang(5))
is used instead of
LANG.
If any internationalization variable contains an invalid setting,
mkstr
behaves as if all internationalization variables are set to "C".
See
environ(5).
International Code Set Support
Single- and multibyte character code sets are supported
within file names, comments, and string literals.
WARNINGS
Strings in calls to functions whose names end in
error,
notably
perror(),
may be replaced with offsets by
mkstr.
Calls to error functions whose first argument is not a string constant
are left unmodified without warning.
Printable version
