ref: 5f7a6b7ea3c4ae1b51beffe3309e9b6b0491e71f
dir: /sys/man/2/quote/
.TH QUOTE 2 .SH NAME quotestrdup, quoterunestrdup, unquotestrdup, unquoterunestrdup, quotestrfmt, quoterunestrfmt, quotefmtinstall, doquote, needsrcquote \- quoted character strings .SH SYNOPSIS .B #include <u.h> .br .B #include <libc.h> .PP .B char *quotestrdup(char *s) .PP .B Rune *quoterunestrdup(Rune *s) .PP .B char *unquotestrdup(char *s) .PP .B Rune *unquoterunestrdup(Rune *s) .PP .B int quotestrfmt(Fmt*) .PP .B int quoterunestrfmt(Fmt*) .PP .B void quotefmtinstall(void) .PP .B int (*doquote)(int c) .PP .B int needsrcquote(int c) .PP .SH DESCRIPTION These routines manipulate character strings, either adding or removing quotes as necessary. In the quoted form, the strings are in the style of .IR rc (1) , with single quotes surrounding the string. Embedded single quotes are indicated by a doubled single quote. For instance, .IP .EX Don't worry! .EE .PP when quoted becomes .IP .EX \&'Don''t worry!' .EE .PP The empty string is represented by two quotes, .BR '' . .PP The first four functions act as variants of .B strdup (see .IR strcat (2)). Each returns a freshly allocated copy of the string, created using .IR malloc (2). .I Quotestrdup returns a quoted copy of .IR s , while .I unquotestrdup returns a copy of .IR s with the quotes evaluated. The .I rune versions of these functions do the same for .CW Rune strings (see .IR runestrcat (2)). .PP The string returned by .I quotestrdup or .I quoterunestrdup has the following properties: .TP 1. If the original string .IR s is empty, the returned string is .BR '' . .TP 2. If .I s contains no quotes, blanks, or control characters, the returned string is identical to .IR s . .TP 3. If .I s needs quotes to be added, the first character of the returned string will be a quote. For example, .B hello\ world becomes .B \&'hello\ world' not .BR hello'\ 'world . .PP The function pointer .I doquote is .B nil by default. If it is non-nil, characters are passed to that function to see if they should be quoted. This mechanism allows programs to specify that characters other than blanks, control characters, or quotes be quoted. Regardless of the return value of .IR *doquote , blanks, control characters, and quotes are always quoted. .I Needsrcquote is provided as a .I doquote function that flags any character special to .IR rc (1). .PP .I Quotestrfmt and .I quoterunestrfmt are .IR print (2) formatting routines that produce quoted strings as output. They may be installed by hand, but .I quotefmtinstall installs them under the standard format characters .B q and .BR Q . (They are not installed automatically.) If the format string includes the alternate format character .BR # , for example .BR %#q , the printed string will always be quoted; otherwise quotes will only be provided if necessary to avoid ambiguity. In .B <libc.h> there are .B #pragma statements so the compiler can type-check uses of .B %q and .B %Q in .IR print (2) format strings. .SH SOURCE .B /sys/src/libc/port/quote.c .br .B /sys/src/libc/fmt/fmtquote.c .SH "SEE ALSO .IR rc (1), .IR malloc (2), .IR print (2), .IR strcat (2)