diff options
Diffstat (limited to 'manual/stdio.texi')
| -rw-r--r-- | manual/stdio.texi | 130 |
1 files changed, 64 insertions, 66 deletions
diff --git a/manual/stdio.texi b/manual/stdio.texi index 0a70b04d75..94f9126c94 100644 --- a/manual/stdio.texi +++ b/manual/stdio.texi @@ -14,7 +14,7 @@ representing a communications channel to a file, device, or process. @menu * Streams:: About the data type representing a stream. * Standard Streams:: Streams to the standard input and output - devices are created for you. + devices are created for you. * Opening Streams:: How to create a stream to talk to a file. * Closing Streams:: Close a stream when you are finished with it. * Streams and Threads:: Issues with streams in threaded programs. @@ -26,17 +26,17 @@ representing a communications channel to a file, device, or process. * Block Input/Output:: Input and output operations on blocks of data. * Formatted Output:: @code{printf} and related functions. * Customizing Printf:: You can define new conversion specifiers for - @code{printf} and friends. + @code{printf} and friends. * Formatted Input:: @code{scanf} and related functions. * EOF and Errors:: How you can tell if an I/O error happens. * Error Recovery:: What you can do about errors. * Binary Streams:: Some systems distinguish between text files - and binary files. + and binary files. * File Positioning:: About random-access streams. * Portable Positioning:: Random access on peculiar ISO C systems. * Stream Buffering:: How to control buffering of streams. * Other Kinds of Streams:: Streams that do not necessarily correspond - to an open file. + to an open file. * Formatted Messages:: Print strictly formatted messages. @end menu @@ -186,13 +186,11 @@ but output is always appended to the end of the file. @end table As you can see, @samp{+} requests a stream that can do both input and -output. The ISO standard says that when using such a stream, you must -call @code{fflush} (@pxref{Stream Buffering}) or a file positioning -function such as @code{fseek} (@pxref{File Positioning}) when switching -from reading to writing or vice versa. Otherwise, internal buffers -might not be emptied properly. The GNU C library does not have this -limitation; you can do arbitrary reading and writing operations on a -stream in whatever order. +output. When using such a stream, you must call @code{fflush} +(@pxref{Stream Buffering}) or a file positioning function such as +@code{fseek} (@pxref{File Positioning}) when switching from reading +to writing or vice versa. Otherwise, internal buffers might not be +emptied properly. Additional characters may appear after these to specify flags for the call. Always put the mode (@samp{r}, @samp{w+}, etc.) first; that is @@ -1109,17 +1107,17 @@ y_or_n_p (const char *question) /* @r{Write a space to separate answer from question.} */ fputc (' ', stdout); /* @r{Read the first character of the line.} - @r{This should be the answer character, but might not be.} */ + @r{This should be the answer character, but might not be.} */ c = tolower (fgetc (stdin)); answer = c; /* @r{Discard rest of input line.} */ while (c != '\n' && c != EOF) - c = fgetc (stdin); + c = fgetc (stdin); /* @r{Obey the answer if it was valid.} */ if (answer == 'y') - return 1; + return 1; if (answer == 'n') - return 0; + return 0; /* @r{Answer was invalid: ask for valid answer.} */ fputs ("Please answer y or n:", stdout); @} @@ -1328,7 +1326,7 @@ situation looks like this: @smallexample f o o b a r - ^ + ^ @end smallexample @noindent @@ -1340,7 +1338,7 @@ situation like this: @smallexample f o o b a r - | + | o-- ^ @end smallexample @@ -1354,7 +1352,7 @@ If you unread @samp{9} instead of @samp{o}, you get this situation: @smallexample f o o b a r - | + | 9-- ^ @end smallexample @@ -1527,19 +1525,19 @@ useful for printing error messages, tables of data, and the like. @menu * Formatted Output Basics:: Some examples to get you started. * Output Conversion Syntax:: General syntax of conversion - specifications. + specifications. * Table of Output Conversions:: Summary of output conversions and - what they do. + what they do. * Integer Conversions:: Details about formatting of integers. * Floating-Point Conversions:: Details about formatting of - floating-point numbers. + floating-point numbers. * Other Output Conversions:: Details about formatting of strings, - characters, pointers, and the like. + characters, pointers, and the like. * Formatted Output Functions:: Descriptions of the actual functions. * Dynamic Output:: Functions that allocate memory for the output. * Variable Arguments Output:: @code{vprintf} and friends. * Parsing a Template String:: What kinds of args does a given template - call for? + call for? * Example of Parsing:: Sample program using @code{parse_printf_format}. @end menu @@ -1561,7 +1559,7 @@ formatted and written to the output stream. For example, int pct = 37; char filename[] = "foo.txt"; printf ("Processing of `%s' is %d%% finished.\nPlease be patient.\n", - filename, pct); + filename, pct); @end smallexample @noindent @@ -2350,20 +2348,20 @@ make_message (char *name, char *value) /* @r{Try to print in the allocated space.} */ nchars = snprintf (buffer, size, "value of %s is %s", - name, value); + name, value); @end group @group if (nchars >= size) @{ /* @r{Reallocate buffer now that we know - how much space is needed.} */ + how much space is needed.} */ size = nchars + 1; buffer = (char *) xrealloc (buffer, size); if (buffer != NULL) - /* @r{Try again.} */ - snprintf (buffer, size, "value of %s is %s", - name, value); + /* @r{Try again.} */ + snprintf (buffer, size, "value of %s is %s", + name, value); @} /* @r{The last call worked, return the string.} */ return buffer; @@ -2452,7 +2450,7 @@ For example: @smallexample #define myprintf(a, b, c, d, e, rest...) \ - printf (mytemplate , ## rest) + printf (mytemplate , ## rest) @end smallexample @noindent @@ -2594,7 +2592,7 @@ For example, take this declaration of @code{eprintf}: @smallexample void eprintf (const char *template, ...) - __attribute__ ((format (printf, 1, 2))); + __attribute__ ((format (printf, 1, 2))); @end smallexample @noindent @@ -2781,30 +2779,30 @@ validate_args (char *format, int nargs, OBJECT *args) int wanted; if (argtypes[i] & PA_FLAG_PTR) - wanted = STRUCTURE; + wanted = STRUCTURE; else - switch (argtypes[i] & ~PA_FLAG_MASK) - @{ - case PA_INT: - case PA_FLOAT: - case PA_DOUBLE: - wanted = NUMBER; - break; - case PA_CHAR: - wanted = CHAR; - break; - case PA_STRING: - wanted = STRING; - break; - case PA_POINTER: - wanted = STRUCTURE; - break; - @} + switch (argtypes[i] & ~PA_FLAG_MASK) + @{ + case PA_INT: + case PA_FLOAT: + case PA_DOUBLE: + wanted = NUMBER; + break; + case PA_CHAR: + wanted = CHAR; + break; + case PA_STRING: + wanted = STRING; + break; + case PA_POINTER: + wanted = STRUCTURE; + break; + @} if (TYPE (args[i]) != wanted) - @{ - error ("type mismatch for arg number %d", i); - return 0; - @} + @{ + error ("type mismatch for arg number %d", i); + return 0; + @} @} return 1; @} @@ -2835,15 +2833,15 @@ The facilities of this section are declared in the header file @menu * Registering New Conversions:: Using @code{register_printf_function} - to register a new output conversion. + to register a new output conversion. * Conversion Specifier Options:: The handler must be able to get - the options specified in the - template when it is called. + the options specified in the + template when it is called. * Defining the Output Handler:: Defining the handler and arginfo - functions that are passed as arguments - to @code{register_printf_function}. + functions that are passed as arguments + to @code{register_printf_function}. * Printf Extension Example:: How to define a @code{printf} - handler function. + handler function. * Predefined Printf Handlers:: Predefined @code{printf} handlers. @end menu @@ -3010,7 +3008,7 @@ You should define your handler functions with a prototype like: @smallexample int @var{function} (FILE *stream, const struct printf_info *info, - const void *const *args) + const void *const *args) @end smallexample The @var{stream} argument passed to the handler function is the stream to @@ -3058,7 +3056,7 @@ You have to define these functions with a prototype like: @smallexample int @var{function} (const struct printf_info *info, - size_t n, int *argtypes) + size_t n, int *argtypes) @end smallexample The return value from the function should be the number of arguments the @@ -3728,7 +3726,7 @@ conversion specification to read a ``variable assignment'' of the form char *variable, *value; if (2 > scanf ("%a[a-zA-Z0-9] = %a[^\n]\n", - &variable, &value)) + &variable, &value)) @{ invalid_input_error (); return 0; @@ -4781,10 +4779,10 @@ provide equivalent functionality. @menu * String Streams:: Streams that get data from or put data in - a string or memory buffer. + a string or memory buffer. * Obstack Streams:: Streams that store data in an obstack. * Custom Streams:: Defining your own streams with an arbitrary - input data source and/or output data sink. + input data source and/or output data sink. @end menu @node String Streams @@ -4958,9 +4956,9 @@ and types described here are all GNU extensions. @menu * Streams and Cookies:: The @dfn{cookie} records where to fetch or - store data that is read or written. + store data that is read or written. * Hook Functions:: How you should define the four @dfn{hook - functions} that a custom stream needs. + functions} that a custom stream needs. @end menu @node Streams and Cookies |