osd@hou2d.UUCP (Orlando Sotomayor-Diaz) (05/15/86)
From: Orlando Sotomayor-Diaz (The Moderator) <cbosgd!std-c>
mod.std.c Digest Thu, 15 May 86 Volume 16 : Issue 18
Today's Topics:
MORE C standard differences Apr85-Feb86, part 8 of 9
----------------------------------------------------------------------
Date:
From: ihnp4!utzoo!lsuc!msb
Subject: MORE C standard differences Apr85-Feb86, part 8 of 9
To: utzoo!ihnp4!hou2d!osd
# D.12.2.1 The clock function
* The clock function returns ... the processor time used {--> by
the program} since the beginning of an implementation-defined era
* {--> related only to the program invocation}.
# D.12.2.2 The time function
N--> The encoding of the value is unspecified.
# D.12.2.2 The time function
* The time function returns ... the current calendar time {since
the beginning of an implementation-defined era -->}.
# D.12.3.1 The asctime function
The asctime function converts the broken-down time in the struc-
* ture pointed to by timeptr into a {26-character -->} string in
* the {following -->} form {. All the fields have constant width.
-->}
Sun Sep 16 01:03:52 1973\n\0
N--> using the equivalent of the following algorithm:
N--> char *asctime(const struct tm *timeptr)
N--> {
N--> static const char wday_name[7][3] = {
N--> "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
N--> };
N--> static const char mon_name[12][3] = {
N--> "Jan", "Feb", "Mar", "Apr", "May", "Jun",
N--> "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
N--> };
N--> static char result[26];
N--> (void) sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
N--> wday_name[timeptr->tm_wday],
N--> mon_name[timeptr->tm_mon],
N--> timeptr->tm_mday, timeptr->tm_hour,
N--> timeptr->tm_min, timeptr->tm_sec,
N--> 1900 + timeptr->tm_year);
N--> return result;
N--> }
# C.12.3.2 The ctime function
N--> It is equivalent to
N--> asctime(localtime(timer))
N--> ... Forward references: the localtime function (#D.12.3.5).
# {--> D.13 FUTURE DIRECTIONS}
# {--> D.13.1 Character handling <ctype.h>}
N--> Function names that begin with "is" and "to" and a lower-case
N--> letter may be added to the declarations in the <ctype.h> header.
# {--> D.13.2 Mathematics <math.h>}
N--> The names of all existing functions declared in the <math.h>
N--> header, suffixed with f or l, are reserved for corresponding
N--> functions with float and long double arguments and return values,
N--> respectively.
# {--> D.13.3 Signal handling <signal.h>}
N--> Macros that begin with SIG and an upper-case letter may be added
N--> to the definitions in the <signal.h> header.
# {--> D.13.4 Input/output <stdio.h>}
N--> The use of leading 0 in fprintf format to request padding with
N--> leading zeros is deprecated. Use the "precision" specifier in-
N--> stead.
N--> Lower-case letters may be added to the conversion specifiers in
N--> fprintf and fscanf. Other characters may be used in extensions.
# {--> D.13.5 String handling <string.h>
N--> Function names that begin with "str" and "mem" and a lower-case
N--> letter may be added to the declarations in the <string.h> header.
# E. APPENDICES
Remark: Since the appendices are not part of the Standard, I have
included only certain ones here. The ones I included were the
new section #E.2 Sequence Points, section #{E.3 --> E.5} Common
Warnings, and section #{E.5 --> E.6} Portability Issues.
# {--> E.2 SEQUENCE POINTS}
N--> The following are the sequence points described in #B.1.2.3.
N--> * The call to a function, after the arguments have been evaluated
N--> (#C.3.2.2).
N--> * The logical AND operator && (#C.3.2.13).
N--> * The logical OR operator || (#C.3.2.14).
N--> * The conditional operator ? (#C.3.2.15).
N--> * The comma operator , (#C.3.2.17).
N--> * Completion of the evaluation of a full expression: an initial-
N--> izer of an object that has automatic storage duration (#C.5.6);
N--> the expression in an expression statement (#C.6.3); the con-
N--> trolling expression of a selection statement (if or switch)
N--> (#C.6.4); the controlling expression of an iteration statement
N--> (while, do, or for) (#C.6.5).
# {E.3 --> E.5} COMMON WARNINGS
* An implicit narrowing conversion is encountered, such as the
* assignment of a long int or a double to an int {-->, or a
pointer to void to a pointer to any type of object other than
char (#C.2)}.
...
<--O * A declaration with no effect is encountered (#C.5).
N--> * An object is defined but not used (#C.5).
# {E.5.1 --> E.6.1} Unspecified behavior
N--> * The behavior if a printable character is written when the ac-
N--> tive position is at the final position of a line (#B.2.2).
N--> * The behavior if a backspace character is written when the ac-
N--> tive position is at the initial position of a line (#B.2.2).
N--> * The behavior if a horizontal tab character is written when the
N--> active position is at or past the last defined horizontal tabu-
N--> lation position (#B.2.2).
N--> * The behavior if a vertical tab character is written when the
N--> active position is at or past the last defined vectical tabula-
N--> tion position (#B.2.2).
# {E.5.1 --> E.6.1} Unspecified behavior
N--> * The order in an array sorted by the qsort function of two
N--> members that compare as equal (#D.10.5.2).
# {E.5.1 --> E.6.1} Unspecified behavior
N--> * The encoding of the calendar time returned by the time function
N--> (#D.12.2.2).
------------------------------
End of mod.std.c Digest - Thu, 15 May 86 13:32:29 EDT
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