diff options
Diffstat (limited to 'src/cmd/cgo/doc.go')
| -rw-r--r-- | src/cmd/cgo/doc.go | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/cmd/cgo/doc.go b/src/cmd/cgo/doc.go index 064725c1d..63413825a 100644 --- a/src/cmd/cgo/doc.go +++ b/src/cmd/cgo/doc.go @@ -52,6 +52,7 @@ C.char, C.schar (signed char), C.uchar (unsigned char), C.short, C.ushort (unsigned short), C.int, C.uint (unsigned int), C.long, C.ulong (unsigned long), C.longlong (long long), C.ulonglong (unsigned long long), C.float, C.double. +The C type void* is represented by Go's unsafe.Pointer. To access a struct, union, or enum type directly, prefix it with struct_, union_, or enum_, as in C.struct_stat. @@ -68,6 +69,21 @@ C compilers are aware of this calling convention and adjust the call accordingly, but Go cannot. In Go, you must pass the pointer to the first element explicitly: C.f(&x[0]). +A few special functions convert between Go and C types +by making copies of the data. In pseudo-Go definitions: + + // Go string to C string + func C.CString(string) *C.char + + // C string to Go string + func C.GoString(*C.char) string + + // C string, length to Go string + func C.GoStringN(*C.char, C.int) string + + // C pointer, length to Go []byte + func C.GoBytes(unsafe.Pointer, C.int) []byte + Cgo transforms the input file into four output files: two Go source files, a C file for 6c (or 8c or 5c), and a C file for gcc. |