inline, noinline, forceinline
Specifies inlining of
all calls in a statement. This also describes pragmas forceinline and
noinline.
Syntax
#pragma inline [recursive]
#pragma forceinline
[recursive]
#pragma noinline
Arguments
- recursive
- Indicates that the pragma applies to all of the calls that are called by these calls, recursively, down the call chain.
Description
inline
,
forceinline
, and
noinline
are statement-specific inlining pragmas. Each can
be placed before a C/C++ statement, and it will then apply to all of the calls
within a statement and all calls within statements nested within that
statement.
The
forceinline
pragma indicates that the calls in question
should be inlined whenever the compiler is capable of doing so.
The
inline
pragma is a hint to the compiler that the user
prefers that the calls in question be inlined, but expects the compiler not to
inline them if its heuristics determine that the inlining would be overly
aggressive and might slow down the compilation of the source code excessively,
create too large of an executable, or degrade performance.
The
noinline
pragma indicates that the calls in question
should not be inlined.
These statement-specific pragmas take precedence over the
corresponding function-specific pragmas.
The
inline
,
forceinline
, and
noinline
pragmas are supported in host code only.
Examples
Use the
forceinline
recursive pragma:
#include <stdio.h>
static void fun(float a[100][100], float b[100][100]) {
inti , j;
for (i = 0; i < 100; i++) {
for (j = 0; j < 100; j++) {
a[i][j] = 2 * i;
b[i][j] = 4 * j;
}
}
}
static void sun(float a[100][100], float b[100][100]) {
int i, j;
for (i = 0; i < 100; i++) {
for (j = 0; j < 100; j++) {
a[i][j] = 2 * i;
b[i][j] = 4 * j;
}
fun(a, b);
}
}
static float a[100][100];
static float b[100][100];
extern int main() {
int i, j;
for (i = 0; i < 100; i++) {
for (j = 0; j < 100; j++) {
a[i][j] = i + j;
b[i][j] = i - j;
}
}
for (i = 0; i < 99; i++) {
fun(a, b);
#pragma forceinline recursive
for (j = 0; j < 99; j++) {
sun(a, b);
}
}
fprintf(stderr, "%d %d\n", a[99][9], b[99][99]);
} The
forceinline recursive
pragma applies to the call
'sun(a,b)' as well as the call 'fun(a,b)' called inside 'sun(a,b)'.