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authorPer Inge Mathisen <per.mathisen@gmail.com>2011-05-11 23:43:26 -0400
committerUlrich Drepper <drepper@gmail.com>2011-05-11 23:43:26 -0400
commit162ba701c2d305ae2fda1e901c85c9004d52b208 (patch)
treed0373e483ab29ecdb8266dfe9a1aa66d2912350b /manual
parente1fb097f447a89aa69a926e45e673a52d86a6c57 (diff)
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Fix manual regarding switch from read to write on streams.
Diffstat (limited to 'manual')
-rw-r--r--manual/stdio.texi130
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