ERR_PTR : 这里PTR是pointer的意思 PTR_ERR IS_ERR #cat hello.c// Defining __KERNEL__ and MODULE allows us to access kernel-level code not usually available to userspace programs.#undef__KERNEL__#define__KERNEL__#undefMODULE#defineMODULE// Linux Kernel/LKM headers: module.h is needed by ...
ERR_PTR,PTR_ERR还有IS_ERR函数详解 内核中的函数常常返回指针,问题是如果出错,也希望能够通过返回的指针体现出来。 总体来说,如果内核返回一个指针,那么有三种情况:合法指针,NULL指针和非法指针。 1)合法指针:内核返回的指针一般是指向页面的边界(4K边界),即ptr & 0xfff == 0 2)非法指针:这样ptr的值不可能落...
union err_t err; memcpy(&err, &val, sizeof(val)); printf("int: %d\n", err.i); printf("long: %ld\n", err.l); printf("unsigned int: %u, 0x%08X\n", err.ui, err.ui); printf("unsigned long: %lu, 0x%08lX\n", err.ul, err.ul); printf("void *: %p\n", err.p); }...
#defineIS_ERR_VALUE(x)unlikely((x)>=(unsigned long)-MAX_ERRNO)staticinlinevoid*__must_checkERR_PTR(long error){return(void*)error;}staticinline long __must_checkPTR_ERR(constvoid*ptr){return(long)ptr;}staticinline long __must_checkIS_ERR(constvoid*ptr){returnIS_ERR_VALUE((unsigned lon...
内核提供include/linux/err.h处理数据类型转换。整型和指针类型转换 在C语言中，数值以补码形式存储。正数存储不变，负数通过取绝对值、取反码、加1实现。以char型-1为例，计算方法如下。使用补码存储数据因设计天才般高效。强制类型转换时，视内存数据（补码）为要转换类型。例如，-1强制转换为unsigned ...
1#defineMAX_ERRNO 409523#ifndef __ASSEMBLY__4EPERM5#defineIS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)6ERROR7staticinlinevoid* __must_check ERR_PTR(longerror)//把错误转化指针8{9return(void*) error;10}1112staticinlinelong__must_check PTR_ERR(constvoid*ptr)//把指针转化...
几个内核函数:filp_open、filp_read、IS_ERR、ERR_PTR、PTR_ERR,程序员大本营,技术文章内容聚合第一站。
[ Upstream commit ef23cb5 ] While debugging a segfault on 'perf lock contention' without an available perf.data file I noticed that it was basically calling: perf_session__delete(ERR_PTR(-1)) Resulting in: (gdb) run lock contention Starting program: /root/bin/perf lock contention [Thread...
函数名称:错误 函数原型:static inline long __must_check PTR_ERR(__force const void *ptr) 返回类型:long 参数: 类型参数名称 __force const void * ptr 31 返回:ptr 调用者 名称描述 err_ptr idr_alloc_u32 bitmap_parselist map_parselist - convert list format ASCII string to bitmap*@buf:...
If devm_gpiod_get_from_of_node() call returns ERR_PTR, it is assigned into an array of GPIO descriptors and used later because such error is not treated as critical thus it is not propagated back to the probe function. All code later expects that such GPIO descriptor is either a NULL...