=head1 NAME perlclib - Internal replacements for standard C library functions =head1 DESCRIPTION One thing Perl porters should note is that F doesn't tend to use that much of the C standard library internally; you'll see very little use of, for example, the F functions in there. This is because Perl tends to reimplement or abstract standard library functions, so that we know exactly how they're going to operate. This is a reference card for people who are familiar with the C library and who want to do things the Perl way; to tell them which functions they ought to use instead of the more normal C functions. =head2 Conventions In the following tables: =over 3 =item C is a type. =item C

is a pointer. =item C is a number. =item C is a string. =back C, C, C, etc. represent variables of their respective types. =head2 File Operations Instead of the F functions, you should use the Perl abstraction layer. Instead of C types, you need to be handling C types. Don't forget that with the new PerlIO layered I/O abstraction C types may not even be available. See also the C documentation for more information about the following functions: Instead Of: Use: stdin PerlIO_stdin() stdout PerlIO_stdout() stderr PerlIO_stderr() fopen(fn, mode) PerlIO_open(fn, mode) freopen(fn, mode, stream) PerlIO_reopen(fn, mode, perlio) (Deprecated) fflush(stream) PerlIO_flush(perlio) fclose(stream) PerlIO_close(perlio) =head2 File Input and Output Instead Of: Use: fprintf(stream, fmt, ...) PerlIO_printf(perlio, fmt, ...) [f]getc(stream) PerlIO_getc(perlio) [f]putc(stream, n) PerlIO_putc(perlio, n) ungetc(n, stream) PerlIO_ungetc(perlio, n) Note that the PerlIO equivalents of C and C are slightly different from their C library counterparts: fread(p, size, n, stream) PerlIO_read(perlio, buf, numbytes) fwrite(p, size, n, stream) PerlIO_write(perlio, buf, numbytes) fputs(s, stream) PerlIO_puts(perlio, s) There is no equivalent to C; one should use C instead: fgets(s, n, stream) sv_gets(sv, perlio, append) =head2 File Positioning Instead Of: Use: feof(stream) PerlIO_eof(perlio) fseek(stream, n, whence) PerlIO_seek(perlio, n, whence) rewind(stream) PerlIO_rewind(perlio) fgetpos(stream, p) PerlIO_getpos(perlio, sv) fsetpos(stream, p) PerlIO_setpos(perlio, sv) ferror(stream) PerlIO_error(perlio) clearerr(stream) PerlIO_clearerr(perlio) =head2 Memory Management and String Handling Instead Of: Use: t* p = malloc(n) New(id, p, n, t) t* p = calloc(n, s) Newz(id, p, n, t) p = realloc(p, n) Renew(p, n, t) memcpy(dst, src, n) Copy(src, dst, n, t) memmove(dst, src, n) Move(src, dst, n, t) memcpy/*(struct foo *) StructCopy(src, dst, t) free(p) Safefree(p) strdup(p) savepv(p) strndup(p, n) savepvn(p, n) (Hey, strndup doesn't exist!) strstr(big, little) instr(big, little) strcmp(s1, s2) strLE(s1, s2) / strEQ(s1, s2) / strGT(s1,s2) strncmp(s1, s2, n) strnNE(s1, s2, n) / strnEQ(s1, s2, n) Notice the different order of arguments to C and C than used in C and C. Most of the time, though, you'll want to be dealing with SVs internally instead of raw C strings: strlen(s) sv_len(sv) strcpy(dt, src) sv_setpv(sv, s) strncpy(dt, src, n) sv_setpvn(sv, s, n) strcat(dt, src) sv_catpv(sv, s) strncat(dt, src) sv_catpvn(sv, s) sprintf(s, fmt, ...) sv_setpvf(sv, fmt, ...) Note also the existence of C and C, combining concatenation with formatting. =head2 Character Class Tests There are two types of character class tests that Perl implements: one type deals in Cs and are thus B Unicode aware (and hence deprecated unless you B you should use them) and the other type deal in Cs and know about Unicode properties. In the following table, C is a C, and C is a Unicode codepoint. Instead Of: Use: But better use: isalnum(c) isALNUM(c) isALNUM_uni(u) isalpha(c) isALPHA(c) isALPHA_uni(u) iscntrl(c) isCNTRL(c) isCNTRL_uni(u) isdigit(c) isDIGIT(c) isDIGIT_uni(u) isgraph(c) isGRAPH(c) isGRAPH_uni(u) islower(c) isLOWER(c) isLOWER_uni(u) isprint(c) isPRINT(c) isPRINT_uni(u) ispunct(c) isPUNCT(c) isPUNCT_uni(u) isspace(c) isSPACE(c) isSPACE_uni(u) isupper(c) isUPPER(c) isUPPER_uni(u) isxdigit(c) isXDIGIT(c) isXDIGIT_uni(u) tolower(c) toLOWER(c) toLOWER_uni(u) toupper(c) toUPPER(c) toUPPER_uni(u) =head2 F functions Instead Of: Use: atof(s) Atof(s) atol(s) Atol(s) strtod(s, *p) Nothing. Just don't use it. strtol(s, *p, n) Strtol(s, *p, n) strtoul(s, *p, n) Strtoul(s, *p, n) Notice also the C, C, and C functions in F for converting strings representing numbers in the respective bases into Cs. In theory C and C may not be defined if the machine perl is built on doesn't actually have strtol and strtoul. But as those 2 functions are part of the 1989 ANSI C spec we suspect you'll find them everywhere by now. int rand() double Drand01() srand(n) { seedDrand01((Rand_seed_t)n); PL_srand_called = TRUE; } exit(n) my_exit(n) system(s) Don't. Look at pp_system or use my_popen getenv(s) PerlEnv_getenv(s) setenv(s, val) my_putenv(s, val) =head2 Miscellaneous functions You should not even B to use F functions, but if you think you do, use the C stack in F instead. For C/C, use C. =head1 SEE ALSO C, C, C