Question

我有一个使用VarLenType

传递ID的函数

我目前正在使用#include <H5Cpp.h> typedef struct mytype_t { double* dprop1; double* dprop2; int* iprop1; double* dprop3; } mytype_t; H5::CompType ctype(sizeof(mytype_t)); auto double_type = H5::PredType::NATIVE_DOUBLE; auto int_type = H5::PredType::NATIVE_INT; auto vdouble_type = H5::VarLenType(&double_type); auto vint_type = H5::VarLenType(&int_type); ctype.insertMember("dProp1", HOFFSET(mytype_t, dprop1), vdouble_type); ctype.insertMember("dProp2", HOFFSET(mytype_t, dprop2), vdouble_type); ctype.insertMember("vProp1", HOFFSET(mytype_t, iprop1), vint_type); ctype.insertMember("dProp3", HOFFSET(mytype_t, dprop3), vdouble_type); std::vector<mytype_t> data_vector; data_vector.resize(dims[0]*dims[1]); dataset.read(data_vector.data(), ctype);将const char* idname与字符串进行比较。例如：

strcmp

我真正想做的是以下内容：

idname

我该如何测试呢？感谢

Answer 1

有这样的库函数：

   Since kernel 2.6.23, the Linux-specific /proc/PID/coredump_filter
   file can be used to control which memory segments are written to the
   core dump file in the event that a core dump is performed for the
   process with the corresponding process ID.

   The value in the file is a bit mask of memory mapping types (see
   mmap(2)).  If a bit is set in the mask, then memory mappings of the
   corresponding type are dumped; otherwise they are not dumped.  The
   bits in this file have the following meanings:

       bit 0  Dump anonymous private mappings.
       bit 1  Dump anonymous shared mappings.
       bit 2  Dump file-backed private mappings.
       bit 3  Dump file-backed shared mappings.
       bit 4 (since Linux 2.6.24)
              Dump ELF headers.
       bit 5 (since Linux 2.6.28)
              Dump private huge pages.
       bit 6 (since Linux 2.6.28)
              Dump shared huge pages.
       bit 7 (since Linux 4.4)
              Dump private DAX pages.
       bit 8 (since Linux 4.4)
              Dump shared DAX pages.

   By default, the following bits are set: 0, 1, 4 (if the
   CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS kernel configuration option is
   enabled), and 5.  This default can be modified at boot time using the
   coredump_filter boot option.

无论您的平台是使用ASCII还是其他内容，这些都可以正常工作。

Answer 2

首先，你应该确保有第一个角色。

if (!idname || !*idname) return;

然后你可以比较你的第一个角色

char firstChar = idname[0];

对抗范围。数字来自＆＃39; 0＆＃39; 0至＆＃39; 9＆＃39;或48至57。小写英文字母来自＆＃39; a＆＃39;到＆＃39; z＆＃39;或97到122。大写字母来自＆＃39; A＆＃39;至＆＃39; Z＆＃39;或65至90。这适用于ASCII字符串。 Unicode可能需要更复杂的算法。

Answer 3

const char* idname = 'a'; // or whatever

if (isalpha(idname )) {
   if ( (int) idname >= 65 && (int) idname <= 90) foo = 2;
   else if ( (int) idname >= 97 && (int) idname <= 122) foo = 3;

} else if (isdigit(c)) {
   foo = 1;
}

这样的事情应该有用。检查一下，我没有测试过。 isalpha（）和isdigit（）是标准函数。

C ++确定var值的第一个字符

3 个答案: