HP-UX Reference (11i v1 00/12) - 3 Library Functions N-Z (vol 7)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man3/nan.3m
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s
scanf(3S) scanf(3S)
25 54.32E-1 thompson
assigns to n the value 3,toi the value 25,tox the value 5.432, and name contains thompson\0. Or:
int i; float x; char name[50];
(void) scanf("%2d%f%*d %[0-9]", &i, &x, name);
with input:
56789 0123 56a72
assigns 56 to i, 789.0 to x, skips 0123, and places the string 56\0 in name. The next call to
getchar() (see getc(3S)) returns a.
For another example, to create a language-independent date scanning routine, use:
char month[20]; int day, year;
(void) scanf(format, month, &day, &year);
For American usage, format would point to a string:
%1$s %2$d %3$d
The input:
July 3 1986
would assign July to month, 3 to day and 1986 to year.
For German usage, format would point to a string:
%2$d %1$s %3$d
The input:
3 Juli 1986
would assign Juli to month, 3 to day and 1986 to year.
The success of literal matches and suppressed assignments can be determined with the %n conversion
specification. Here is an example that checks the success of literal matches:
int i, n1, n2, n3, n4;
n1 = n2 = n3 = n4 = -1;
scanf("%nBEGIN%n %d %nEND%n", &n1, &n2, &i, &n3, &n4);
if (n2 - n1 == 5) puts( "matched BEGIN");
if (n4 - n3 == 3) puts( "matched END");
Here is an example that checks the success of suppressed assignments:
int i, n1, n2;
n1 = n2 = -1;
scanf( "%d %n%*s%n", &i, &n1, &n2);
if (n2 > n1)
printf("successful assignment suppression of %d chars\n", n2-n1);
APPLICATION USAGE
scanf(), fscanf() and sscanf() are thread-safe. These interfaces are not async-cancel-safe. A
cancellation point may occur when a thread is executing scanf() or fscanf().
After scanf() or fscanf() is applied to a stream, the stream becomes byte-oriented (see orienta-
tion(5)).
WARNINGS
Trailing white space (including a newline) is left unread unless matched in the control string.
Truncation of multi-byte characters may occur if a field width is used with the conversion character.
AUTHOR
scanf() was developed by AT&T and HP.
Section 3−−828 − 4 − HP-UX Release 11i: December 2000
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